Aspects of this invention relate generally to testing of electronic elements, and more particularly to an apparatus and system for testing a number of electronic elements such as semiconductor devices using a number of probes, and to a method for sorting a number of electronic elements into a number of receptacles.
Electronic elements such as semiconductor devices typically undergo testing prior to various stages of packaging. FIG. 1 is a simplified diagram of a typical electronic element 100, such as a diode, which includes an active element 102 in chip form (typically silicon) doped with small amounts of boron, arsenic, phosphorus, zinc, germanium, or other elements. Active element 102 is in contact with terminal regions 104. Two terminal regions 104 are shown, although additional terminal regions are possible. Terminal regions 104 may take the form of thin layers of metals such as aluminum, gold or titanium prior to being bonded to a lead frame (not shown). After bonding to a lead frame, terminal regions 104 may take the form of gold or aluminum wires.
Prior to various stages of packaging electronic element 100, such as prior to attaching a lead frame thereto, and/or prior to enclosing electronic element 100 in a case of glass, plastic or metal, it is desirable to use terminal regions 104 to measure certain electrical characteristics of electronic element 100 using probes and a testing circuit—similar devices with satisfactory electrical characteristics may then be separated from devices with unsatisfactory electrical characteristics.
Probes are conductive elements that contact terminal regions 104 of an electronic element 100, and provide at least a portion of an electrical path to a testing circuit. As shown in FIG. 1, a probe 105 has an upper pole 106 in contact with one terminal region 104 of electronic element 100, and has a lower pole 108 in contact with another terminal region 104, although more than two terminal regions of electronic element 100 may be in contact with probes.
Examples of measured electrical characteristics of a diode include, but are not limited to, reverse current of the diode, forward voltage of the diode, and reverse breakdown voltage of the diode. A schematic diagram of a testing circuit 200 suitable for testing diode reverse current (IR) is shown in FIG. 2, and a schematic diagram of a testing circuit 300 suitable for testing diode forward voltage (VF) is shown in FIG. 3.
In one conventional testing technique, semiconductor devices are tested and sorted individually—one-by-one, devices are mechanically transferred to and from a testing station, where they are electrically connected to probes and testing circuits.
Another known testing technique involves testing several (usually less than ten) devices in a single cycle at a testing station. In the latter technique, probes are connected to switches using wire cable, and the switches are responsive to testing circuits. Switches and testing circuits are often integrated onto switching boards.
One factor that reduces the efficiency of manufacturing and/or assembly operations of semiconductor devices is the amount of time the devices spend being transferred to and from testing stations. One way to reduce device transfer time during testing is to increase the number of devices tested per cycle. The complexity of corresponding testing hardware and control generally increases, however, in proportion to the number of devices tested per cycle. In particular, (1) the volume and complexity of wire cables connecting probes with switching boards increases, making the testing hardware more difficult to maintain or re-configure, and (2) performing post-testing sorting operations, including the management of testing results, becomes more difficult. Maintenance, reconfiguration, and result management difficulties are further exacerbated when devices of different shapes, sizes and electrical characteristics are tested in the same cycle.
There are therefore needs for apparatuses, systems, and methods for testing electronic elements, which increase efficiency of testing processes, while enhancing serviceability and configurability of testing hardware.